Steam-generating plant.



M. W. SEWALL.

STEAM GENERATING PLANT.

APPLIOATION FILED HAYS, 1909.

Patented Mar; 14, 1911.

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M. W. SBWALL. STEAM GENERATING PLANT.

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Patented Mar. 14, 1911.

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M. W. SEWALL.

STEAM GENERATING PLANT.

AYPLIUATION FILED MAYB, 1909.

Patented Mar. 14, 1911.

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ATTORNEYS M. W. SEWALL.

STEAM GENERATING PLANT. APPLICATION TILED MAYG, 1909.

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M. W; SEWALL. STEAM GENERATING PLANT.

APPLICATION FILED HAYS, 1909. 1 986,648. Patented Mar. 14, 1911.

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M. W. SEWALL. STEAM GENERATING PLANT.

-APILIOATION IILED MAYB, 1909.

Patented Mar.14,191-1.

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STEAM GENERATING PLANT. A'PPLIOATION TILED mus, 1909.

Patented Mar. 14, 1911.

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' INVENTOR- WITNESSES ATTORNE rs Tu: mamas UNITED STATES PATENT OFFICE.

MINOT'I W. SEWALL, OF ROSELLE, NEW JERSEY, ASSIGNOR TO THE BABCOCK & WILCOX COMPANY, OF BAYONNE, NEW JERSEY, A CORPORATION OF NEW JERSEY.

STEAM-GENERATING PLANT.

Specification of Letters Patent.

Patented Mar. 14, 1911.

Application filed May 6, 1909. Serial No. 494,383.

To all whom it may concern:

Be it known that I, Mlno'r'r \V. bnwaiin, a citizen of the United States, residing at Roselle, in the county of Union and State of New Jersey, have invented certain new and useful Improvenients in Steam-Generating Plants, of which the following is a specification.

An object of the present invention is to concentrate within a limited floor area a maximum of grate surface so arranged rela-, tively to the water tube heating surface as to obtain a maximum evaporation per square foot of floor area occupied, this object being suggested by the boiler setting described and claimed in my application Serial No. 455,767, filed October 1, 1908, wherein the furnace grate surfaces extend. over the floor spaces between contiguous boilers.

A further object is to so arrange the water tube heating surface that the greater part of said surface shall be forced to its maximum capacity, and a minor portion of it shall serve as awaste heat economizer, and that the gases shall escape free from smoke and at a low degree of temperature. This object is attained by inclosing an economizer boiler or feed water heater between contiguous boilers, and disposed relatively thereto in such manner as to utilize the gases from the boilers and to prevent loss of heat due to radiation from the walls. For the boilers proper and their furnaces I have shown a construction substantially similar to that described and claimed in the application of Minott \V. Sewall and David S. Jacobus, Serial No. 477310, filed February 11, 1909.

Another object is to so arrange the heating surface that free access shall be had to all exterior surfaces for cleaning, and surfaces permitting radiation and infiltration shall be small.

In brief my invention contemplates a plant using standard commercial parts that shall give an output of steam greater than is usual per square foot of heating surface and floor area, and with better economy than is usual with plants occupying larger floor areas.

Probabl the reasons for seeking the above objects wil be more clearly understood if the method of operation of large, modern steam plan-ts were clearly stated. Such plants are usually designed on what is called the Unit system that is to say, a certain number of boilers are arranged to deliver steam to a given stean'i-using apparatus, and the whole steam plant itself consists in a multiple of such units connected only by whatare designated as steam cross-over pipes, such pipes being of suitable diameter to convey the steam from one steanrgenerat ing unit to the adjacent steam-using unit. If such a steam plant is operating under a variable load it becomes necessary, for a large part of the day, to keep many of the boilers under steam by maintaining banked fires in the furnaces in order that they shall be ready for a hurried call for a large production of steam. Such calls are produced in electric light stations by a shower during the business day, which may result in the turning on of a large number of lights within five or ten minutes, and in street railway plants by the busy portions of the night and morning. The banking of fires mentioned is a wasteful process, and it is to avoid to a large extent the waste of that process that the present design has been made. It is found that if a boiler plant is capable of an exceedingly large production of steam for a short time, even though it be done with but poor economy, that the ability of such large production is of great value, as less boilers are then required than otherwise. On the other hand,-during the greater portions of the day, when the load on the plant is comparatively small, it becomes necessary to produce steam at the utmost economy. This steam-generating unit has been designed first to produce steam at a high economy and, second, to produce a very large amount of steam at the shortest notice.

In the accompanying drawings I have shown a steamgenerating unit of two boilers and one economizer, boiler placed between the two. All of these are mounted above two furnaces which occupy the width of the three boilers plus a sufficient width of floor space for a cleaning passage. The waste heat economizer may be used as a boiler for the generation of steam or as a feed water heater, and the term economizer used in the following description is intended to include both.

My invention will be understood by reference to the accompanying drawings in Which Figure 1 is a front elevation of two boiler units showing a. passageway between and at the sides of the units; Fig. 2 a vertical transverse section on the plane of the line .2--2 of Figs. 3, 4 and 6; Fig. 3 a vertical longitudinal section on the plane of the line S--3 of liig. 2; Fig. 4 a vertical longitudinal section on the plane of the line 4--4 of Fig. 2; Fig. 5 a horizontal. section on the plane of the line 5 B of Fig. 3; Fig. (3 a horizontal section on the plane of the line G-tj of Fig. 8; Fig. 7 a. trai'isverse vertical. section on the plane of the line 77 of Fig. 3; vIiig. 8 a vertical longitudinal section on the plane of the line 88 of Fig. 9; Fig. 9 a transverse vertical section on the plane of the line 9*9 of Fig. 8; Fig. 10 a horizontal section on the plane of the line 1111 of Fig. 8.

Similar reference numerals indicate similar parts in the several views.

Figs. 1 to 7 illustrate an adaptation of my invention to an inclined water tube boiler, and Figs. 8 to 10 an adaptation applied to the Stirling type of boiler. Referring to Figs. 1 to 7, I have shown two units each comprising two boilers 11 and an economizer 2 all placed above two furnaces t l-A3. The furnaces of the two units occupy the entire surface laterally of the units including that provided for the cleaning passageways 4.

Although I have shown but two units, it. is to be understood that there may be additional, or any number, of units that may be required for a given installation.the only requirement being that between each two units there shall be a cleaning passageway 4.

The end walls of the furnaces and the parting walls (3 are of ordinary fire brick and built up to the height of the inclined roof. These furnaces may be of any usual construction provided with grates and doors, or automatic stokers, the grate surface extending from wall to wall. The roof is formed of inclined water tubes 7 inclosed in special fire clay tiles 8, said tiles extending rearwardly to the wall 10 beneath the economizer 2, and to the rear of the bridge walls 11 beneath the boilers 1-1, as shown in Figs. 3, 4 and 6. The extension of the furnace roof in this manner provides an exit opening 12 for the gases into passage 13 di rectly beneath the tubes of the boilers 11. The roof tubes 7 are expanded into manifolds 35 and 36 which are connected to the section headers 17 and 18 respectively through nipples 14 and 15. The mud drums 37 of boilers 1'1 are also nippled to manifolds 36 which have blow-off connections 38, as shown in Figs. 3 and 4.

The boilers 1-1 comprise water tubes 16 set inclined downwardly to the rear and connected to the section headers 17 and 18. The secondary roof 19 is supported on the lower row of tubes and extends from the first gas passage across the tubes to the rear header 18, such construction presenting the advantages fully set forth in the above application Serial No. 477,410. To secure the proper circulatiol'i of the gases through and across the tubes any efiicient. form of battling may be used. I have shown vertical partition walls 20 and 21 and horizontal baffles 22, 22-3 and 24. The wall 20 extends across all. of the tubes, and the wall 21 extends from the steam drum 25 to the top tube and across a portion of the tubes. Baflles 22 and 24. extend rcarwardly from Wall 21, and baffle 23 extends forwardly from header 18 intermediate the bafiies 22 and 24. This disposition of the walls and bafiies provides two direct cross passes and three partial horizontal passes.

The economizer 2 comprises inclined water tubes 20 expanded into headers 27 and 28 connected to steam drum 29. The course of the gases directed by baflies 30, 31 and 32 disposed longitudinally of the tubes, as shown in Fig. 4. It may be desirable to introduce additional baffles to increase the number of passes over the tubes. The rear headers 28 are all nippled into mud drum 33 having a blow-off connection 34.

It will be seen that there are two independent furnaces for each unit, and, as indicated by the arrows in Figs. 8 to 7, the gases pass from the furnaces 3-3 through passages 12and l3 beneath the boilers 11. Fig. 3, over the heating surfaces of said boilers as directed by the walls and baffles above described, over the top of headers 18 and downwardly to the lower part of chamber 39 at the rear of wall 10. In this chamber the gases from the boilers 1--1 commingle and then pass into passage 40 under the economizer 2, then over the heating surface of said boiler as directed by the battles, to the flue connection 41.

The parts of the boiler unit are symmetrically disposed relatively to the parting wall 6 of a given unit. This permits of the utilization of the entire floor space for grate surface required by the boilers and cleaning passages. For the purpose of cleaning the exterior tube surfaces of the boilers 11 I provide dusting doors -42 opposite each horizontal space between rows of tubes, as shown in Figs. 2 and 3. These doors are in the side walls of the boilers above the floor of passages 4 and readily accessible for the purpose of cleaning the boiler tubes of dust and soot. This cleaning is accomplished by means of a steam jet carried by a pipe four or five feet in length with a special form of nozzle, the workmen passing along the pas sageway between the boiler units.

As the economizer is completely inclo-sed on its sides by the boilers 11, other means of cleaning are necessary. For such purpose a. central passage 43 is provided by a lateral separation of the tubes entering the headers 27 and 28 at or near the center of tween the headers of boiler 2 are required to prevent short circuiting of the flue gases.

The water tube roofs of the furnaces are inadequate for supporting the boiler walls above them. For this reason the walls 46 and 47 are so constructed as to be supported by the adjacent boiler tubes. As shown in Fig. 2, a special form of recessed brick is employed in which the outside sections of tubes of the boilers are seated, such tubes directly supporting the four walls and relieving the furnace roof of their weight. As there is considerable space between the lower tubes of the boiler and the furnace roofs, special tubes 48 are introduced as an extension of the outside sections of boilers 11 (Figs. 2 and t). These tubes 48 are expanded into short manifolds 49 and 50, said manifolds being nippled to the headers 17 and 18 of the outside boilers, and to the manifolds 35 and 36 (Figs. 3, 4 and 7). To properly support the special fire brick, tubes 48 may be completely inclosed in the fire brick tiles, as shown in Fig. 2.

All of the tubes and headers are filled with water, the normal water level being the center line of the drums 25. The circulation is from said drums down through headers 1S, tubes 16, special tubes 48, furnace roof tubes 7, to header 17. If the circulation is inadequate, I may introduce extra supply and discharge pipes 51 and 52 (Fig. at) leading respectively from the rear ends of the drums 29 to manifolds 36, and from manifolds to the front ends of the drums.

In order that the economizer may be an efficient absorber of heat, its heating surface and gas passages are proportioned to the area of the gas passages of the boilers 11, it being borne in mind that the gases of said boilers are combined in a passage leading to the economizer and that their volume is greatly reduced at the lower temperatures.

I do not confine myself to the particular gas passages described. If desired, instead of causing the gases to pass out of boilers l1 in the manner described, I may take them off through a passage 53, shown in clotted lines in Figs. 3 and t, above the tubes at the rear of the boilers, thus reversing the flow of the gases through the economizer. This change would necessitate the closing of passage 54 at the rear of wall 10 and conducting the gases out through the rear wall of boiler 2 near the floor line. If the gas passages areso arranged that the gases from boilers 1-1 are directed through passage 39 under the economizer, through passage 40, an advantage is gained in that the radiant heat through the walls and floor of passage 40 tends to increase the heat of the gases in said passage approaching the economizer. On the other hand, by using passages 53 the gases have a more direct course to the economizer and no opportunity is afforded for loss of heat by radiation fromthe surrounding walls. A disadvantage in taking the gases through passage 53 lies in the fact that the radiation from the walls and floor of passage 40 will be carried directly to the stack.

The end boilers of each unit installed above the furnaces have a small heating surface relatively to the grate surface, and the excess heat is fully utilized by the economizer between the inner walls of the boilers.

In Figs. 8 to 10 I have shown my invention applied to the Stirling type of boiler. In this adaptation of the invention the fur naces cover the entire floor area, contiguous furnaces being separated by the parting wall 6 as before described. The end boilers of each unit comprise the usual front, middle and rear banks of tubes 55, 56 and 57, connected to the water and steam drums 58, and mud drum 59. Baflle walls 60 direct the course of the gases up and across the front bank, down and across the middle bank, and up across the rear bank of tubes to the passage 61, where the gases from the two boilers commingle and flow througl1 passage G2 to the economizer. The latter is of cross-drum type and comprises the inclined tubes 63 expanded into headers 64: connected to cross-drum 65, the rear header directly and the front header through the pipes 68. The inside walls 66, separating the boilers from the economizer, are supported on the arched furnace roofs 67 and are reinforced by I-beams, as shown in Fig. 9.

Normally the dampers 74: in the outlets from the boilers to the main flue are closed. By opening them and closing damper 73 in the outlet from the boilers to the economizer, the gases will pass directly from the boilers to the main flue and will not pass through the economizer.

hat I claim and desire to secure by Letters Patent of the United States is 1. A steam-generating plant comprising two adjacent furnaces, a boiler installed above each furnace, and an economizer i11- stalled between the said boilers and embraced within the boiler setting, each fur-' nace and its boiler being independently operated. V

2. A steam-generating plant comprising two adjacent furnaces, a boiler installed above each furnace, an economizer installed between said boilers above the furnaces, and. partition walls so disposed as to cause the gases from said boilers to pass through the economizer, each furnace and its boiler be ing independently operated.

3. A steam-generating plant comprising two adjacent independently operated furnaces, a water tube boiler installed above each furnace, a water tube economizer installed between the boilers, and a fire brick wall between the boilers and the economizer, the bricks of said walls being supported by the adjacent tube sections of the boilers and economizer.

l. A steam-generating plant comprising two boilers spaced apart and comprising inclined tubes, an economizer installed between the inner walls of said boilers, said walls consisting of bricks having recesses to embrace so as to be supported by the tubes of the outside sect-ions of the boiler and economizer, said boilers being independently operated.

5. A steam-generating plant comprising two adjacent and independently operated furnaces, a boiler installed above each furnace, an economizer installed between the inner walls of said boilers, a roof for said furnaces, and walls forming passages with said roof to direct the gases from the boilers to the economizer.

G. A steam-generating plant comprising two adjacent furnaces, a water tube boiler installed above each furnace, a water tube economizer installed between the boilers, special tubes constituting an extension of the outside sections of the boilers, manifolds into which said tubes are expanded, and connections between said manifolds and 'the boiler headers. said furnaces and boilers being independently operated.

7. A steam-generating plant comprising two adjacent furnaces, a boiler installed above each furnace, said boilers comprising tubes and headers, a downward extension from the outside sections of tubes, said extension being formed of manifolds and tubes connected by nipples to the lower ends of the headers, and a fire brick wall supported by said tubular extensions.

8. In a steam-generating plant comprising two adjacent furnaces, a water tube boiler installed above each furnace, an economizer installed between the boilers, a roof for said furnaces extending from the front wall rearwardly to cut off direct connection between the furnaces and the economizer, the said roof consisting of tubes, manifolds into which said tubes are expanded, and connections between said manifolds and the boiler headers, said furnaces and boilers being independently operated.

9. In combination, two adjacent furnaces, a boiler installed above each furnace, an economizer installed between the boilers, a roof for said furnaces extending from the front wall rearwardly to cut off direct connection between the furnaces and the economizer, partition walls rising from said roof and separating the boilers and economizer, and a wall at the rear of the boilers, said walls forming passages to cause the gases approaching the economizer to be reheated by the radiation from the boiler walls.

10. A steam-generating plant comprising two adjacent boilers spaced apart, an economizer installed between the boilers and having walls in common therewith, furnaces for said boilers and economizer, and par tition walls forming'passages to direct the gases through the boilers and to cause them to pass into contact with the boiler walls as they approach the economizer to thereby reheat said gases, each furnace and its boiler being independently operated.

11. In combination, two adjacent and independent furnaces, a boiler installed above each furnace, an economizer installed between the two boilers, the roof of said furnaces extending late ally beneath the boilers and partially beneath the economizer to thereby cut off direct connection between the furnaces and the economizer and to provide an exit opening for the gases into passages directly beneath the boilers.

12. In combination, two adjacent and independent furnaces each having a boiler of inclined tubes installed above it, an economizer installed between said boilers,a roof for said furnaces consisting of water tubes partially or fully inclosed in fire clay tiles and extending laterally beneath the boilers and partially beneath said economizer, and a secondary roof for each boiler supported on the lower row of tubes and extending from the first gas passage to the rear header.

In testimony whereof I have hereunto signed my name in the presence of two subscribing witnesses.

MINOTT SETVALL. lVitnesses FRANK E. RAFFMAN, CHARLES S. JoNns.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, I). C. 

